Temperature control device for engine

ABSTRACT

A temperature control device for the engine may include an air heater configured to heat air introduced into a throttle valve by a flow of engine cooling water, and a valve apparatus configured to cut off the flow of the engine cooling water passing through the air heater at a set temperature range or more, without being supplied with a separate control signal.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Applications No.10-2014-0175172, filed on Dec. 8, 2014 and No. 10-2015-0041567, filed onMar. 25, 2015, the entire contents of which are which incorporatedherein for all purposes by this reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a temperature control device for anengine, and more particularly, to a technology of controlling atemperature of a throttle body of the engine to which an exhaust-gasrecirculation (EGR) is applied.

Description of Related Art

In an engine to which an EGR re-circulating exhaust gas of the engine toa front end of a throttle body of an intake system of the engine isapplied, when a temperature of air received into the intake system is asub-zero temperature like a winter season, a phenomenon that moistureincluded in EGR gas re-circulated into the intake system of the enginefreezes by meeting air below zero occurs, in which the freezingphenomenon hinders a valve flap included in the throttle body fromrotating to cause an abnormal phenomenon which makes it difficult tosmoothly control a fuel-air mixture introduced into the engine, reducesan output of the engine, and the like.

Generally, the fuel-air mixture or air received into the engine needs tobe supplied to the engine in a low temperature state if possible withina range in which side effects due to the freezing phenomenon describedabove do not occur to improve filling efficiency of the engine, therebyobtaining the higher output of the engine.

The information disclosed in this Background of the Invention section isonly for enhancement of understanding of the general background of theinvention and should not be taken as an acknowledgement or any form ofsuggestion that this information forms the prior art already known to aperson skilled in the art.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing atemperature control device for an engine capable of preventing a motionobstruction phenomenon of a valve flap from occurring due to moisturefreezing in an engine to which EGR is applied while air mixed with EGRgas passes through a throttle valve to prevent air passing through thethrottle valve from being excessively heated while securing smooth andstabilized workability of the engine, thereby preventing fillingefficiency of the engine from being unnecessarily reduced.

According to various aspects of the present invention, a temperaturecontrol device for the engine may include an air heater configured toheat air introduced into a throttle valve by a flow of engine coolingwater, and a valve apparatus configured to cut off the flow of theengine cooling water passing through the air heater at a set temperaturerange or more, without being supplied with a separate control signal.

The air heater may be provided between a position where an exhaust gasrecirculation (EGR) passage, through which EGR gas is supplied, isconnected to an intake pipe of the engine and a position where a valveflap of the throttle valve connected to the intake pipe is disposed.

A first end of the intake pipe may be coupled to a throttle body whichis provided with the throttle valve therein, and the air heater may beintegrally formed at the first end of the intake pipe which is coupledto the throttle body.

The air heater may include a heating channel which is formed in an arcshape within the first end of the intake pipe so as to provide the flowof cooling water while enclosing a circumference of air introduced intothe throttle body, a supply port provided at the first end of the intakepipe so as to supply the cooling water to the heating channel, and adischarge port provided at the first end of the intake pipe so as todischarge the cooling water through the heating channel.

The air heater may be coupled between an end of the intake pipe and athrottle body and may include a heating adapter of which a center isprovided with an air hole through which air passes from the intake pipeto the throttle body, and the heating adapter may be provided with aheating channel so as to allow cooling water to flow while enclosing acircumference of the air hole and may be provided with a support portwhich supplies the cooling water to the heating channel and a dischargeport which discharges the cooling water through the heating channel.

The heating adapter may be integrally provided with an extending pipewhich protrudes to be inserted into the throttle body from an edgeportion of the air hole to heat air passing through the air hole over along period of time while increasing a heat transfer to the throttlevalve due to conduction.

The air heater may be integrally provided at an upstream side of thethrottle valve within a throttle body.

The valve apparatus may include a thermostat which cuts off coolingwater discharged from the engine through an engine passage from flowingin a heat radiation passage toward a radiator when a temperature of thecooling water is less than the set temperature range and cuts off thecooling water from the engine passage from flowing through a bypasspassage for directly supplying the cooling water to a water pump whilebypassing the radiator when the temperature of the cooling water exceedsthe set temperature range.

The thermostat which is the valve apparatus may be configured to cut offa circulation passage through which cooling water passing through theair heater is connected to the bypass passage when a second valve cutsoff the bypass passage through which the cooling water is directlysupplied to the water pump when the temperature of the cooling waterexceeds the set temperature range.

The circulation passage may be formed to communicate with a surface of avalve seat seated when the second valve of the thermostat cuts off thebypass passage.

The engine may be a compressed natural gas (CNG) engine using CNG asfuel, the air heater may be disposed to be supplied with the coolingwater passing through an air compressor to cool the air compressorcompressing air to be used in a vehicle to heat air supplied to thethrottle valve, the cooling water passing through the air heater and thevalve apparatus may be directly supplied to a water pump which isconfigured to pump the cooling water to the engine, and the aircompressor is disposed to be supplied with the cooling water passingthrough the engine.

The cooling water passing through the air compressor may be supplied toa fuel heater which is configured to heat the CNG to be supplied to theengine, in addition to the air heater, and the cooling water passingthrough the fuel heater may be transferred to the water pump.

According to various aspects of the present invention, a thermostat foran engine may include a first valve configured to cut off a heatradiation passage, through which cooling water discharged from theengine through an engine passage is supplied to a radiator, from theengine passage when a temperature of the cooling water is less than aset temperature range, a second valve configured to interlock with thefirst valve and cut off a bypass passage, through which the coolingwater discharged from the engine through the engine passage is directlysupplied to a water pump, from the engine passage when the temperatureof the cooling water exceeds the set temperature range, and acirculation port having an end opened on a surface of a valve seat ofthe second valve so as to transfer the cooling water discharged from theengine through a separate passage from the engine passage and allow thecooling water to flow in the bypass passage and then to be cut off assoon as the second valve cuts off the bypass passage.

It is understood that the term “vehicle” or “vehicular” or other similarterms as used herein is inclusive of motor vehicles in general such aspassenger automobiles including sports utility vehicles (SUV), buses,trucks, various commercial vehicles, watercraft including a variety ofboats and ships, aircraft, and the like, and includes hybrid vehicles,electric vehicles, plug-in hybrid electric vehicles, hydrogen-poweredvehicles and other alternative fuel vehicles (e.g., fuel derived fromresources other than petroleum). As referred to herein, a hybrid vehicleis a vehicle that has two or more sources of power, for example, bothgasoline-powered and electric-powered vehicles.

The methods and apparatuses of the present invention have other featuresand advantages which will be apparent from or are set forth in moredetail in the accompanying drawings, which are incorporated herein, andthe following Detailed Description, which together serve to explaincertain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a portion of a compressed natural gas(CNG) engine to which the present invention is applied.

FIG. 2 is a diagram illustrating an intake pipe, a throttle body, and anintake manifold when viewed from the top of FIG. 1.

FIG. 3 is a diagram illustrating a cross section taken along the line ofFIG. 2 and a state in which the throttle body is separated from theintake pipe.

FIG. 4 is a diagram illustrating an air heater according to the presentinvention.

FIG. 5 is a diagram illustrating a cooling water circulating system of aCNG engine to which the present invention is applied and a state inwhich the air heater heats air.

FIG. 6 is a diagram illustrating a state in which the air heater doesnot heat air, as compared with FIG. 5.

FIG. 7 is a diagram of a thermostat structure according to the presentinvention and illustrates a thermostat state under the situation inwhich the air heater heats air.

FIG. 8 is a compared diagram with FIG. 7 illustrating the thermostatstate under the situation in which the air heater does not heat air.

It should be understood that the appended drawings are not necessarilyto scale, presenting a somewhat simplified representation of variousfeatures illustrative of the basic principles of the invention. Thespecific design features of the present invention as disclosed herein,including, for example, specific dimensions, orientations, locations,and shapes will be determined in part by the particular intendedapplication and use environment.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of thepresent invention(s), examples of which are illustrated in theaccompanying drawings and described below. While the invention(s) willbe described in conjunction with exemplary embodiments, it will beunderstood that present description is not intended to limit theinvention(s) to those exemplary embodiments. On the contrary, theinvention(s) is/are intended to cover not only the exemplaryembodiments, but also various alternatives, modifications, equivalentsand other embodiments, which may be included within the spirit and scopeof the invention as defined by the appended claims.

Referring to FIG. 1 to FIG. 8, a temperature control device for anengine according to various embodiments of the present inventionincludes an air heater 1 provided to heat air introduced into a throttlevalve by a flow of engine cooling water and a valve apparatus 30provided to cut off the flow of engine cooling water passing through theair heater 1 at a set temperature range or more without being suppliedwith a separate control signal.

In this configuration, the air heater 1 is provided between a positionwhere an EGR passage 3 through which EGR gas is supplied is connected toan intake pipe 5 of the engine E and a position where a valve flap ofthe throttle valve 7 connected to the intake pipe 5 is installed.

That is, even though EGR gas is mixed under the situation in which airhaving a sub-zero temperature is introduced through an intake pipe 5,the air heater 1 heats the air to prevent a valve flap of the throttlevalve 7 from freezing, thereby preventing various kinds of side effectslike the reduction in output from the engine E which occurs due to thehindrance of motion of the valve flap, and so on and the valve apparatus30 cuts off the flow of cooling water of the air heater 1 under thesituation that the engine E is sufficiently warmed up to eliminate thefreezing concerns of the throttle valve 7 so as to prevent the airintroduced in to the engine E from being unnecessarily heated, therebypreventing filling efficiency of the engine E from being reduced due totemperature rising of received air.

As illustrated in FIG. 2 and FIG. 3, one end of the intake pipe 5 iscoupled with the throttle body 9 which is provided in the throttle valve7, the throttle body 9 is connected to an intake manifold 11 throughwhich the received air is distributed into each combustion chamber ofthe engine E, and the air heater 1 is integrally formed at an end of theintake pipe 5 which is coupled with the throttle body 9.

In this configuration, the air heater 1 is configured to include aheating channel 13 which is formed in an arc shape within the end of theintake pipe 5 so as to provide a flow of cooling water while enclosing acircumference of air introduced into the throttle body 9, a supply port15 provided at the end of the intake pipe 5 so as to supply the coolingwater to the heating channel 13, and a discharge port 17 provided at theend of the intake pipe 5 so as to discharge the cooling water throughthe heating channel 13.

Therefore, the engine E cooling water is introduced through the supportport 15 and thus passes through the end of the intake pipe 5 whileflowing in the heating channel 13 to heat the air transferred to thethrottle valve 7 and is discharged through the discharge port 17.

Meanwhile, the air heater 1 may be configured as a separate part asillustrated in FIG. 4 and the air heater 1 of FIG. 4 is coupled betweenthe end of the intake pipe 5 and the throttle body 9 and is configuredof a heating adapter 19 of which the center is provided with an air hole21 through which air passes from the intake pipe 5 to the throttle body9.

In this configuration, the heating adapter 19 is provided with theheating channel 13 so as to provide the flow of cooling water whileenclosing the circumference of the air hole 21 and is provided with asupport port 15 which supplies the cooling water to the heating channel13 and a discharge port 17 which discharges the cooling water throughthe heating channel 13.

Further, the heating adapter 19 is integrally provided with an extendingpipe 23 protruding to be inserted into the throttle body 9 from an edgeportion of the air hole 21 to heat air passing through the air hole 21over a long period of time while increasing a heat transfer to thethrottle valve 7 due to conduction, thereby maximizing a heating effectof air and heating the throttle valve 7 itself.

Although not illustrated in the drawings, according to variousembodiments of the air heater 1, the air heater 1 may be integrallyprovided at an upstream side of the throttle valve 7 within the throttlebody 9.

That is, the engine E cooling water is configured to integrally includethe support port, the heating channel, the discharge port, and the likeas described above, to heat the air passing through the throttle valve 7in advance while flowing in the throttle body 9 itself.

Meanwhile, the valve apparatus 30 is configured of a thermostat 31 whichcuts off the cooling water discharged from the engine E through anengine passage 25 from flowing in the heat radiation passage 27 towardthe radiator R when a temperature of cooling water is less than a settemperature range and cuts off the cooling water from the engine passage25 from flowing through the bypass passage 29 for directly supplying thecooling water to the water pump (W/P) while bypassing the radiator Rwhen a temperature of cooling water exceeds a set temperature range.

That is, a wax pellet type thermostat 31, and the like expands andcontracts wax present therein depending on a temperature of coolingwater without being applied with a separate control signal from acontrol device such as a controller to control the flow of coolingwater. The various embodiments of the present invention are configuredto control the flow of cooling water passing through the air heater 1,along with the thermostat 31.

That is, the thermostat 31 is generally configured to include a firstvalve 33 configured to cut off the heat radiation passage 27, throughwhich the cooling water discharged from the engine E through the enginepassage 25 is supplied to the radiator R, from the engine passage 25when the temperature of cooling water is less than a set temperaturerange, and a second valve 35 configured to interlock with the firstvalve 33 and cut off the bypass passage 29, through which the coolingwater discharged from the engine E through the engine passage 25 isdirectly supplied to the water pump W/P, from the engine passage 25 whenthe temperature of cooling water exceeds the set temperature range, andin addition to the components, the thermostat 31 used in variousembodiments of the present invention includes a circulation port 37configured to have an end opened on a surface of a valve seat 36 of thesecond valve 35 so as to transfer the cooling water discharged from theengine E through a separate passage from the engine passage 25 and makethe cooling water flow in the bypass passage 29 and then to be cut offas soon as the second valve 35 cuts off the bypass passage 29.

Therefore, the thermostat 31 which is the valve apparatus 30 is formedto allow the circulation passage 39 to communicate with the surface ofthe valve seat 36 seated when the second valve 35 cuts off the bypasspassage 29 if the second valve 35 cuts off the bypass passage 29 throughwhich the cooling water is directly supplied to the water pump W/P whenthe temperature of cooling water exceeds the set temperature range, andtherefore is configured to cut off the circulation passage 39 throughwhich the cooling water passing through the air heater 1 is connected tothe bypass passage 29, along with the second valve 35.

In this configuration, the circulation port 37 forms a portion of thecirculation passage 39 and is an expression which represents a portionof the circulation passage 39 configured in the thermostat 31 and thecirculation passage 39 means the cooling water passage which is reachedfrom the discharge port 17 of the air heater 1 to the circulation port37.

Meanwhile, the set temperature range of the thermostat 31 may be set tobe, for example, 82° C. to 92° C. In this case, when the temperature ofcooling water is less than 82° C., the first valve 33 cuts off the heatradiation passage 27 to prevent the cooling water discharged from theengine E through the engine passage 25 from being supplied to the heatradiation passage 27 and directly supplies the cooling water to thewater pump W/P through the bypass passage 29 to again circulate thecooling water to the engine E, when the temperature of cooling waterexceeds 82° C., the first valve 33 starts to be opened and the secondvalve interlocking thereto starts to be closed, and when the temperatureof cooling water reaches 92° C., the second valve 35 is completelyclosed and thus the bypass passage 29 is cut off from the engine passage25. According to various embodiments of the present invention, thecirculation passage 39 is cut off simultaneously therewith and the flowof cooling water of the air heater 1 stops.

According to various embodiments of the present invention illustrated inFIG. 1, FIG. 5, and FIG. 6, the engine E is a compressed natural gas(CNG) engine using compressed natural gas as fuel, the air heater 1 isinstalled to be supplied with the cooling water passing through an aircompressor 41 to cool the air compressor 41 compressing air to be usedin the vehicle to heat the air supplied to the throttle valve 7, thecooling water passing through the air heater 1 and the thermostat 31which is the valve apparatus 30 is directly supplied to the water pumpW/P which pumps the cooling water to the engine E, and the aircompressor 41 is installed to be supplied with the cooling water passingthrough the engine E.

The cooling water passing through the air compressor 41 is supplied to afuel heater 43 which heats the CNG to be supplied to the engine E, inaddition to the air heater 1 and the cooling water passing through thefuel heater 43 is transferred to the water pump W/P.

An action of the present invention configured as described above will bedescribed with reference to FIG. 5 and FIG. 6.

The state of FIG. 5 is a situation that the warm up of the engine E isnot sufficiently made and moisture in the EGR gas may freeze by receivedcold air but illustrates a situation that the air heater 1 heats the airsupplied toward the throttle valve 7 to prevent the freezing and thestate of FIG. 5 is a state in which the cooling water discharged fromthe engine E is supplied to the water pump W/P through the bypasspassage 29 and is a state in which the cooling water which is dischargedfrom the engine E and passes through the air compressor 41 and the airheater 1 is circulated to the water pump W/P by sequentially passingthrough the circulation passage 39 and the bypass passage 29.

In this state, the cooling water which is supplied with heat from theengine E and is discharged is additionally supplied with heat whilecooling the air compressor 41 and is heated and then is supplied to theair heater 1 to heat the air to be provided to the throttle valve 7 at arelatively higher temperature, thereby more effectively preventing thefreezing problem of the throttle valve 7.

FIG. 6 illustrates a situation after the warm up of the engine E issufficiently made. In this situation, there is no risk that the throttlevalve 7 which is adjacently positioned to the engine E within an engineE room may freeze due to the heat sufficiently generated from the engineE in advance. Rather, when the air heater 1 heats an air received intothe engine E, the filling efficiency of the engine is reduced andtherefore FIG. 6 illustrates a situation to prevent the reduction infilling efficiency.

That is, the engine E is sufficiently warmed up to allow the secondvalve 35 to cut off the bypass passage 29 and under the situation thatthe all cooling water discharged from the engine E passes through theradiator R through the heat radiation passage 27 and then is circulatedto the water pump W/P, since the circulation passage 39 is also cut offby the second valve 35, the air heater 1 is no longer supplied with thecooling water transferring heat and therefore does not heat the airsupplied to the combustion chamber through the throttle valve 7.

Even in this case, however, the air compressor 41 is continuouslysupplied with the cooling water and thus is cooled. In this situation,the cooling water passing through the air compressor 41 is circulated tothe water pump W/P through the fuel heater 43 and therefore the aircompressor 41 is continuously cooled.

According to various embodiments of the present invention, it ispossible to prevent the motion obstruction phenomenon of the valve flapfrom occurring due to moisture freezing in an engine to which EGR isapplied while air mixed with EGR gas passes through a throttle valve toprevent air passing through the throttle valve from being excessivelyheated while securing smooth and stabilized workability of the engine,thereby preventing filling efficiency of the engine from beingexcessively reduced.

The foregoing descriptions of specific exemplary embodiments of thepresent invention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteachings. The exemplary embodiments were chosen and described in orderto explain certain principles of the invention and their practicalapplication, to thereby enable others skilled in the art to make andutilize various exemplary embodiments of the present invention, as wellas various alternatives and modifications thereof. It is intended thatthe scope of the invention be defined by the Claims appended hereto andtheir equivalents.

What is claimed is:
 1. A temperature control device for an engine,comprising: an air heater configured to heat air introduced into athrottle valve by a flow of engine cooling water; and a valve apparatusconfigured to cut off the flow of the engine cooling water passingthrough the air heater at a set temperature range or more, without beingsupplied with a separate control signal from a controller so as to cutoff the flow of the engine cooling water independently from thecontroller, wherein the valve apparatus comprises a thermostat whichcuts off cooling water discharged from the engine through an enginepassage from flowing in a heat radiation passage toward a radiator whena temperature of the cooling water is less than the set temperaturerange and cuts off the cooling water from the engine passage fromflowing through a bypass passage for directly supplying the coolingwater to a water pump while bypassing the radiator when the temperatureof the cooling water exceeds the set temperature range, and wherein thethermostat which is the valve apparatus is configured to cut off acirculation passage through which cooling water passing through the airheater is connected to the bypass passage when a second valve cuts offthe bypass passage through which the cooling water is directly suppliedto the water pump when the temperature of the cooling water exceeds theset temperature range.
 2. The temperature control device for the engineof claim 1, wherein the air heater is provided between a position wherean exhaust gas recirculation (EGR) passage, through which EGR gas issupplied, is connected to an intake pipe of the engine and a positionwhere a valve flap of the throttle valve connected to the intake pipe isdisposed.
 3. The temperature control device for the engine of claim 2,wherein a first end of the intake pipe is coupled to a throttle bodywhich is provided with the throttle valve therein, and the air heater isintegrally formed at the first end of the intake pipe which is coupledto the throttle body.
 4. The temperature control device for the engineof claim 3, wherein the air heater includes: a heating channel which isformed in an arc shape within the first end of the intake pipe so as toprovide the flow of cooling water while enclosing a circumference of airintroduced into the throttle body; a supply port provided at the firstend of the intake pipe so as to supply the cooling water to the heatingchannel; and a discharge port provided at the first end of the intakepipe so as to discharge the cooling water through the heating channel.5. The temperature control device for the engine of claim 2, wherein theair heater is coupled between an end of the intake pipe and a throttlebody and includes a heating adapter of which a center is provided withan air hole through which air passes from the intake pipe to thethrottle body, and the heating adapter is provided with a heatingchannel so as to allow cooling water to flow while enclosing acircumference of the air hole and is provided with a support port whichsupplies the cooling water to the heating channel and a discharge portwhich discharges the cooling water through the heating channel.
 6. Thetemperature control device for the engine of claim 5, wherein theheating adapter is integrally provided with an extending pipe whichprotrudes to be inserted into the throttle body from an edge portion ofthe air hole to heat air passing through the air hole over a long periodof time while increasing a heat transfer to the throttle valve due toconduction.
 7. The temperature control device for the engine of claim 2,wherein the air heater is integrally provided at an upstream side of thethrottle valve within a throttle body.
 8. The temperature control devicefor the engine of claim 1, wherein the circulation passage is formed tocommunicate with a surface of a valve seat seated when the second valveof the thermostat cuts off the bypass passage.
 9. The temperaturecontrol device for the engine of claim 1, wherein the engine is acompressed natural gas (CNG) engine using CNG as fuel, the air heater isdisposed to be supplied with the cooling water passing through an aircompressor to cool the air compressor compressing air to be used in avehicle to heat air supplied to the throttle valve, the cooling waterpassing through the air heater and the valve apparatus is directlysupplied to a water pump which is configured to pump the cooling waterto the engine, and the air compressor is disposed to be supplied withthe cooling water passing through the engine.
 10. The temperaturecontrol device for the engine of claim 9, wherein the cooling waterpassing through the air compressor is supplied to a fuel heater which isconfigured to heat the CNG to be supplied to the engine, in addition tothe air heater, and the cooling water passing through the fuel heater istransferred to the water pump.